This invention relates to carbonating apparatus, being apparatus for introducing a gas into a liquid, especially the introduction of carbon dioxide into a liquid, usually water, for the production of carbonated beverages.
Carbon dioxide conventionally is introduced into water which may or may not contain concentrate flavouring.
Where the water contains no concentrate flavouring, some times referred to as a syrup, carbonated water is produced, and this carbonated water may either be used for consumption or mixing in which form it is known as soda water, or the carbonated water may subsequently be mixed with a quantity of concentrate in order to provide a flavoured beverage. In the latter case, the carbonated water may be mixed with a syrup in a beverage dispensing machine, for example of the type set forth in U.S. Pat. No. 4,523,697, which essentially is designed for in-home use, or the carbonated water may be mixed with a syrup in a dispensing head of a commercial machine such as is conventionally used in restaurants, soda fountains, bars and the like.
Again, there is the factory production installation for the production of carbonated water and/or beverages, wherein a large scale carbonating plant carbonates water or water containing flavouring syrup in order to produce carbonated water and/or beverage which subsequently is bottled or canned for distribution to supermarkets and other retail outlets attended by the members of the public.
This invention has application to all of these circumstances, and in general has as its concept the introduction of a gas into a liquid, especially the introduction of carbon dioxide into water, and when the apparatus performs the latter function it is known as a carbonator. In the interests of simplicity of description, reference is made herein only to "carbonator" when referring to the apparatus, and reference is made only to carbon dioxide and water in referring to the gas and the liquid which are contacted so that the gas will be absorbed by the liquid.
The carbonating of water it will be appreciated has been practiced for many years, and a number of methods are utilized for achieving the absorption of the carbon dioxide into the water, the objective understandably always being to achieve maximum rates of absorption or in other words the take-up of the maximum amount of carbon dioxide into the water in the minimum period of time. In all cases, the carbon dioxide and water are brought into intimate contact and the carbon dioxide is absorbed into the water. The rate at which absorption takes place depends upon a number of factors including the following:
1. The temperature at which contact takes place, the general rule being that the lower the temperature which contact takes place, the higher the absorption. PA0 2. The area of contact between the water and the carbon dioxide, the general rule being that the larger the contact area, the better the rate of absorption. PA0 3. The pressure under which contact takes place in that the higher the pressure the higher the absorption and the higher the rate of absorption.
One of the most commonly practiced methods of bringing the water and carbon dioxide gas into contact, is to bubble the carbon dioxide gas into the lower end of a body of water contained in a carbonator and which is to be carbonated, the gas being bubbled into the carbonator in as small bubbles as possible in order to achieve maximum contact area. The temperature of the water is kept low again in order to achieve maximum absorption rates.
Other carbonators use contra flow systems. That is to say the water and carbon dioxide are caused to contact whilst flowing in opposite directions, the carbon dioxide bubbling through the water in as small bubbles as possible in order to achieve maximum contact area.
In other carbonating devices, the carbon dioxide is induced into a jet of water for example created by passing the water through a Venturi device, the carbon dioxide being aspirated into the throat of the Venturi in small bubbles in order to achieve high speed carbonation.
In yet other forms, the water is atomized into a very fine spray or mist by being forced at a high pressure through a small orifice, and the atomized water is flooded into a carbon dioxide environment. The water particles constitute a large surface area giving a large surface area of contact between the carbon dioxide and water leading to a high rate of absorption.
Of the known prior art systems outlined above, the best performance in terms of rate of absorption is achieved by the atomizing of the water to create a fine water particle or droplet mist which is flooded into a carbon dioxide atmosphere for example in a carbonator tank, but the main difficulty with this apparatus is that because of the pressures in the supply line of water necessary for achieving the fine atomization, expensive, high performance pumps are required and the expenditure involved in the purchase and maintenance of the pumps, because they operate at high speed and are prone to failure.
Producers of carbonated water therefore often utilize one of the other systems, the most common being the bubbling of the carbon dioxide gas into the lower end of a body of liquid, and tolerate relatively slow rates of carbon dioxide absorption and in some cases relatively poor levels of carbonation in favour of a system which operates reliably although rather slowly.
As to the matter of chilling the water in order to achieve a higher rate of up-take of carbon dioxide, a number of proposals are known in this regard, amongst which includes surrounding the carbonator with cooling coils or embodying such coils inside the carbonator, or in the alternative arranging for the cooling of the water prior to its being introduced into the carbonator, at a downstream location in the water supply circuit.